Pristomerus species of Madagascar are revised. We report 15 species, of which 12 are newly described: P. guinness sp. nov., P. hansoni sp. nov., P. kelikely sp. nov., P. keyka sp. nov., P. moramora sp. nov., P. melissa sp. nov., P. patator sp. nov., P. ranomafana sp. nov., P. roberti sp. nov., P. vahaza sp. nov., P. veloma sp. nov. and P. yago sp. nov. Pristomerus albescens (Morley) and P. cunctator Tosquinet are newly recorded from Madagascar and new host and/or distribution records are provided for this species. A dichotomous key to all species is provided. The zoogeographical relation of the Malagasy fauna of Pristomerus with respect to mainland Africa is discussed: only three of the 15 species are reported to occur outside of Madagascar, suggesting a high level of endemism in Madagascar which was not unexpected.
Parasitic wasps, Indian Ocean, biodiversity hotspot, taxonomy, description.